Numerous attempts have been made in the past to increase the extractability of roast coffee of those flavorful water-soluble constituents often referred to as brew solids. That is, attempts have been made to increase the amount of brew solids which are able to be extracted from a given weight of coffee from which a coffee brew is made.
It has long been known that the extractability of roast coffee could be increased by grinding the coffee to finer particle sizes. However, roast coffee products ground to very fine grinds have bed-permeability characteristics which inhibit the extraction of the water-soluble constituents due to bed compaction, pooling, channeling, etc. To avoid such brewing problems, it has been conventional to provide roast coffee ground to mixtures of variously sized particles, such as the traditional grinds of "regular", "drip" and "fine".
Other than adjusting the particle size distribution by grinding, relatively little effort has been directed toward altering the fundamental physical characteristics of coffee. Green coffee beans have been roll-milled prior to roasting and grinding to increase the extractability of coffee (see U.S. Pat. No. 2,123,207, issued July 12, 1938 to Rosenthal). Roast and ground coffee has been light-milled to provide a coffee product which has the same bulk appearance as conventional roast and ground coffee but which has increased extractability (see U.S. Pat. No. 3,769,031, issued Oct. 26, 1973 to J. R. McSwinggin). Flaked green coffee has also been subjected to compressive and shear forces via extruder roasting to provide a roast coffee product which yields higher soluble solids (see, for example, U.S. Pat. No. 3,762,930, issued Oct. 2, 1973 to J. P. Mahlmann). Although these efforts may result in some level of improvement in extracting desirable coffee flavor constituents, further enhancement of coffee's extractability is provided by flaked roast and ground coffee.
Roast and ground coffee has been transformed into flaked coffee by roll milling the roast and ground coffee (see, for example, U.S. Pat. No. 1,903,362, issued Apr. 4, 1933 to R. B. McKinnis and U.S. Pat. No. 2,368,113, issued Jan. 30, 1945 C. W. Carter). Thick-flaked (i.e., flaked coffee having an average flake thickness greater than 0.008 inch) roast and ground of enhanced extractability is disclosed by Joffe in U.S. Pat. No. 3,615,667, issued Oct. 26, 1971 as well as a method for its production in U.S. Pat. No. 3,660,106, issued May 2, 1972 to J. R. McSwiggin et al. A visually appealing high-sheen flaked roast and ground coffee of improved extractability is disclosed in U.S. Pat. No. 4,110,485, issued Aug. 29, 1978 to Grubbs.
In contrast to the consumer acceptability of thick-flaked roast and ground coffee, both the Joffe '667 patent and the McSwiggin '106 patent teach that thin-flaked coffee having an average flake thickness of less than 0.008 inch is taught to be consumer-unacceptable. The thin-flaked coffee produced by such prior art methods is described as having a "cellophane-like" nature and, therefore, visually unappealing. Moreover, the "cellophane-like" thin flakes are also disclosed as being undesirably fragile and have both an unacceptably low and a variable bulk density (Joffe '667, Column 8, lines 46-54).
The prior art teaches that the fragile nature of the thin flakes of the prior art leads to product breakup during normal packaging, transportation and handling. The product breakup is accompanied by the flakes aligning themselves in parallel planes producing a very compact product with a bulk density substantially higher than that of roast and ground coffees presently marketed. When the parallel plane alignment takes place after packaging, there occurs an objectionable increase in container outage (i.e. the space between the upper surface of the product and the upper surface of the container). Large container outages are viewed negatively by the consumer. Thus, the thin-flaked roast and ground coffee produced by art-known methods is consumer unacceptable.
Given the state of the coffee art as described above, there is a continuing need to provide a roast and ground coffee product which provides improved extractability of soluble brew solids and which possesses consumer acceptable physical properties and appearance. Accordingly, it is an object of the present invention to provide a roast and ground coffee product exhibiting desirable organoleptic and physical properties.
The methods known in the art for preparing flaked roast and ground coffee comprise passing roast and ground coffee through a roll mill under particular conditions of roll pressure, roll peripheral speed, roll temperature, roll diameters, and flake moisture content. While known methods of making flaked coffee having realized thick-flaked roast and ground coffee which provides an extractability advantage compared to conventional roast and ground coffee and possesses consumer acceptable flake physical properties, these methods have been unable to produce thin-flaked roast and ground coffee exhibiting desirable physical properties.